Method and device for identifying type of filling medium of well-passing crack beside shale reservoir horizontal well
Through the pre-processing and imaging processing of array acoustic well logging data, fracture imaging maps and reflection amplitude curves of Stoneley wave and dipole transverse wave are generated, which solves the problem of identifying fracture filling media types in the horizontal well of shale reservoirs and realizes the Efficient and accurate identification of fluid and solid media types.
Patent Information
- Application Number
- CN202311081542.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-25
- Publication Date
- 2025-02-25
AI Technical Summary
The prior art is difficult to effectively identify and distinguish the types of filling media in the cracks of the horizontal well next to the shale reservoir, especially calcite solid substances and oil, gas, and water fluid substances.
By collecting and preprocessing the array acoustic logging data, the waveform and time difference of Stoneley wave and dipole transverse wave are obtained respectively, noise suppression and imaging are performed, and the fracture imaging map and reflection amplitude curve of Stoneley wave and dipole transverse wave are generated, and the type of fracture filling medium next to the well is determined.
Efficient and accurate identification of the types of overwell fracture filling media next to horizontal wells of shale reservoirs is achieved, and the shortcomings of the prior art are overcome and the types of fluid and solid media can be distinguished.
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Figure CN119507901A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of unconventional reservoir oil and gas exploration, and in particular relates to a method and a device for identifying the type of filling medium of a horizontal well bypassing a shale reservoir. Background Art
[0002] In the exploration and development of oil and gas resources worldwide, the evaluation and analysis of geological information such as fractured mudstone, carbonate rock, and shale is one of the problems that need to be solved urgently in today's logging technology. In China, the proportion of fractured low-permeability reservoirs is very prominent, and the oil and gas production of fractured low-permeability reservoirs accounts for more than half of the total oil and gas production. Early exploration and development practices have shown that fractures are an important factor affecting the development effect of deep shale gas. On the one hand, fractures play a role in communicating oil and gas and increasing the permeability of reservoirs. On the other hand, fractures may cause casing deformation, pressure channeling and other accidents. Therefore, identifying and evaluating wellside fractures, especially fractures that pass through the wellbore, is of guiding significance for formulating reasonable development and production plans for unconventional reservoirs.
[0003] Morris et al. (1964) first studied the relationship between the amplitude of longitudinal and transverse waves and the width of fractures in acoustic logging data. Paillet (1980) discovered and studied the attenuation of shear waves at fractures in array acoustic logging data. Zlatev et al. (1988) used physical experiments to simulate the propagation of acoustic waves at fractures through the well, and pointed out that passing through fractures would greatly reduce the amplitude of shear waves. In the same year, physical experimental studies found that the attenuation of the amplitude of Stoneley waves increased with the increase of fracture width, and the attenuation of the amplitude of Stoneley waves was affected by the inclination of fractures. Hornby et al. (1989) assumed that the formation was rigid and derived the relationship between the reflection coefficient of Stoneley waves and the fracture width in the case of horizontal fractures and in the case of inclined fractures. Fan et al. (2013) and Li et al. (2019) studied the response of Stoneley waves to fractures through shock tube experiments.
[0004] The above research content mainly focuses on how to use borehole mode waves, such as the velocity and attenuation properties of direct P-waves and direct S-waves, to distinguish wellbore fractures. However, the types of filling media in horizontal wellbore fractures in shale reservoirs, especially the distinction between calcite solids and oil, gas, and water fluids, have not been involved. Summary of the invention
[0005] In order to effectively identify the filling medium type of fractures passing by a well, the present invention proposes a method and device for identifying the filling medium type of fractures passing by a horizontal well in a shale reservoir.
[0006] A method for identifying the type of filling medium for a horizontal well bypass fracture in a shale reservoir comprises the following steps:
[0007] Collecting array acoustic logging data of the target well, wherein the array acoustic logging data at least mainly includes the original waveform, gain curve and delay curve of the monopole array acoustic logging, and the original waveform, gain curve and delay curve of the dipole array acoustic logging;
[0008] Preprocess the array acoustic logging data to obtain the waveform and time difference of Stoneley wave, the waveform and time difference of dipole shear wave;
[0009] Perform noise suppression and imaging processing on the waveform of Stoneley wave and the waveform of dipole shear wave respectively to obtain Stoneley wave crack imaging map and dipole shear wave crack imaging map;
[0010] The Stoneley wave reflection amplitude is calculated based on the Stoneley wave fracture imaging image to obtain the Stoneley wave reflection amplitude curve of the well; the dipole shear wave reflection amplitude is calculated based on the dipole shear wave fracture imaging image to obtain the dipole shear wave reflection amplitude curve of the well;
[0011] The type of filling medium of the fractures near the wellbore is identified based on the Stoneley wave fracture imaging map, reflection amplitude curve, dipole shear wave fracture imaging map, and dipole shear wave reflection amplitude curve.
[0012] Furthermore, the array acoustic logging data is preprocessed to obtain the waveform and time difference of Stoneley waves, the waveform and time difference of dipole shear waves, including:
[0013] The array acoustic logging data are subjected to gain recovery, delay recovery and bandpass filtering to obtain the waveform and time difference of Stoneley waves and the waveform and time difference of dipole shear waves respectively.
[0014] Furthermore, the array acoustic logging data is subjected to gain recovery, delay recovery and bandpass filtering, including:
[0015] Gain recovery is performed according to the following gain parameter AGN:
[0016] AGN=10 GN*0.05
[0017] Among them, GN is the collected gain curve;
[0018] For monopole array acoustic logging data, the frequency band of the bandpass filter is 600 Hz-3000 Hz, and for dipole array acoustic logging data, the frequency band of the bandpass filter is 3000 Hz-5500 Hz.
[0019] Furthermore, noise suppression and imaging processing are performed on the waveform of the Stoneley wave and the waveform of the dipole shear wave, respectively, to obtain a Stoneley wave crack imaging map and a dipole shear wave crack imaging map, including:
[0020] FK filtering is used to suppress noise on the waveform of Stoneley wave and the waveform of dipole shear wave respectively, so as to obtain the reflected wave signal of Stoneley wave and the reflected wave signal of dipole shear wave;
[0021] The uplink and downlink waves of the Stoneley wave reflection signal are separated to obtain two Stoneley wave uplink reflection waves and downlink reflection waves, with a Stoneley wave fracture imaging map of the wellbore in the middle; the uplink and downlink waves of the dipole shear wave reflection signal are separated to obtain two Stoneley wave uplink reflection waves and downlink reflection waves, with a Stoneley wave fracture imaging map of the wellbore in the middle.
[0022] Furthermore, the Stoneley wave reflection amplitude is calculated based on the Stoneley wave fracture imaging image to obtain the Stoneley wave reflection amplitude curve of the well, including:
[0023] The coordinates of the intersection of the fracture and the wellbore are obtained from the Stoneley wave fracture imaging map;
[0024] Using the intersection coordinates of the fracture and the wellbore, the Stoneley wave time difference D Stoneley Get the coordinates of any point on the inclined phase axis of the crack;
[0025] The amplitude values of all points at the same depth are summed to obtain the Stoneley wave reflection amplitude at the same depth;
[0026] The Stoneley wave reflection amplitudes at different depths are calculated in sequence to obtain the Stoneley wave reflection amplitude curve of the well.
[0027] Furthermore, using the intersection coordinates of the fracture and the wellbore, the Stoneley wave time difference D Stoneley Obtaining the coordinates of any point on the inclined phase axis of the crack includes calculating the coordinates (t1, h1) of any point on the inclined phase axis of the crack according to the following formula:
[0028]
[0029] Among them, t0 is the abscissa of the intersection of the fracture and the wellbore, representing time; h0 is the ordinate of the intersection of the fracture and the wellbore, representing depth; Δt is the known time increment, and the unknown depth increment Δh is obtained by the following formula:
[0030]
[0031] Among them, D Stoneley The Stoneley wave time difference.
[0032] Furthermore, the dipole shear wave reflection wave amplitude is calculated based on the dipole shear wave fracture imaging image, and the dipole shear wave reflection amplitude curve of the well is obtained, including:
[0033] The coordinates of the intersection of the fracture and the wellbore are obtained from the dipole shear wave fracture imaging map;
[0034] Using the intersection coordinates of the fracture and the wellbore, the dipole shear wave time difference D S Get the coordinates of any point on the inclined phase axis of the crack;
[0035] The amplitude values of all points at the same depth are summed to obtain the dipole shear wave reflection amplitude at the same depth;
[0036] The dipole shear wave reflection amplitudes at different depths are calculated in sequence to obtain the dipole shear wave reflection amplitude curve of the well.
[0037] Furthermore, using the intersection coordinates of the fracture and the wellbore, the dipole shear wave time difference D S Obtaining the coordinates of any point on the inclined phase axis of the crack includes calculating the coordinates (t1, h1) of any point on the inclined phase axis of the crack according to the following formula:
[0038]
[0039] Among them, t0 is the abscissa of the intersection of the fracture and the wellbore, representing time; h0 is the ordinate of the intersection of the fracture and the wellbore, representing depth; Δt is the known time increment, and the unknown depth increment Δh is obtained by the following formula:
[0040]
[0041] Among them, D S is the dipole shear wave time difference.
[0042] Furthermore, based on the Stoneley wave fracture imaging map, reflection amplitude curve, dipole shear wave fracture imaging map, and dipole shear wave reflection amplitude curve, the type of the filling medium of the fracture near the wellbore is identified, including:
[0043] If at a certain depth, both the Stoneley wave fracture inclined phase axis and the dipole shear wave fracture inclined phase axis appear, and the corresponding reflection amplitudes of the two respond, it is judged that there is a through-well fracture at this depth, and the filling medium type in the fracture is fluid; if at a certain depth, there is no Stoneley wave fracture inclined phase axis, but there is a dipole shear wave fracture inclined phase axis, it means that there is a through-well fracture at this depth, and the filling medium type in the fracture is solid.
[0044] In another aspect, the present invention also discloses a device for identifying the type of filling medium for a horizontal well bypassing a shale reservoir, comprising a logging data collection module, a logging data preprocessing module, a fracture imaging module, a reflection amplitude curve generation module, and an identification module, wherein:
[0045] The logging data collection module is used to collect conventional logging data and array acoustic logging data of the target well, wherein the conventional logging data at least includes a gamma curve; the array acoustic logging data at least mainly includes a monopole array acoustic original waveform, a gain curve and a delay curve, and a dipole array acoustic logging original waveform, a gain curve and a delay curve;
[0046] The logging data preprocessing module is used to preprocess the array acoustic logging data to obtain the waveform and time difference of the Stoneley wave and the waveform and time difference of the dipole shear wave respectively;
[0047] The crack imaging module is used to perform noise suppression and imaging processing on the waveform of the Stoneley wave and the waveform of the dipole shear wave, respectively, to obtain a Stoneley wave crack imaging map and a dipole shear wave crack imaging map;
[0048] The reflection amplitude curve generating module is used to calculate the Stoneley wave reflection amplitude based on the Stoneley wave fracture imaging map to obtain the Stoneley wave reflection amplitude curve of the well; calculate the dipole shear wave reflection wave amplitude based on the dipole shear wave fracture imaging map to obtain the dipole shear wave reflection amplitude curve of the well;
[0049] The identification module is used to identify the type of filling medium of the wellbore fracture based on the Stoneley wave fracture imaging image and reflection amplitude curve, the dipole shear wave fracture imaging image and the dipole shear wave reflection amplitude curve.
[0050] Based on the above technical solution, the beneficial effects of the present invention compared with the prior art are as follows:
[0051] Based on numerical simulation and physical experiments of a large number of horizontal wellside fracture models in shale reservoirs, the present invention finds that array acoustic logging data can be used to identify the type of filling medium in wellside fractures, so that the Stoneley wave fracture imaging map and reflection amplitude curve, dipole shear wave fracture imaging map and dipole shear wave reflection amplitude curve of the target well to be identified are obtained respectively, and comparative analysis is performed to determine whether the filling medium type of wellside fractures is fluid or solid. The embodiment of the present invention can efficiently and accurately identify the filling medium type in the fracture as fluid or solid, overcoming the shortcomings of the prior art. BRIEF DESCRIPTION OF THE DRAWINGS
[0052] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0053] Figure 1The present invention is a flowchart of a method for identifying the type of filling medium for a horizontal well bypass fracture in a shale reservoir in the first embodiment of the present invention.
[0054] Figure 2 This is a Stoneley wave fracture imaging diagram in Example 1 of the present invention.
[0055] Figure 3 This is a dipole shear wave crack imaging diagram in Example 1 of the present invention.
[0056] Figure 4 This is a schematic diagram of a method for calculating reflection amplitude using Stoneley wave or dipole shear wave imaging data in Embodiment 1 of the present invention.
[0057] Figure 5 This is a schematic diagram of calculating the Stoneley wave reflection amplitude and determining the through-well fracture depth using Stoneley wave imaging data in Example 1 of the present invention.
[0058] Figure 6 This is a schematic diagram of calculating the dipole shear wave reflection amplitude and determining the through-well fracture depth using dipole shear wave imaging data in the first embodiment of the present invention.
[0059] Figure 7 This is a schematic diagram of identifying the type of filling medium of a wellbore fracture using a Stoneley wave fracture imaging diagram, a reflection amplitude curve, a dipole shear wave fracture imaging diagram, and a dipole shear wave reflection amplitude curve in the first embodiment of the present invention.
[0060] Figure 8 This is another schematic diagram of identifying the type of filling medium of a wellbore fracture using the Stoneley wave fracture imaging image, the reflection amplitude curve, the dipole shear wave fracture imaging image, and the dipole shear wave reflection amplitude curve in the first embodiment of the present invention.
[0061] Fig. 9 This is a schematic structural diagram of a device for identifying the type of filling medium for a horizontal well bypassing a shale reservoir fracture in a second embodiment of the present invention. DETAILED DESCRIPTION
[0062] Based on a large number of numerical simulations and physical experiments of fracture models near horizontal wells in shale reservoirs, the inventors have found certain rules to determine whether the fracture filling medium type is solid or fluid. Specifically, the inventors found that: if the filling medium type in the fracture is fluid (the fluid specifically refers to oil, natural gas or water), then the Stoneley wave fracture imaging map, Stoneley wave reflection amplitude curve, dipole shear wave fracture imaging map, and dipole shear wave reflection amplitude curve of the well will have the following characteristics: at a certain depth, the Stoneley wave fracture inclined phase axis and the dipole shear wave fracture inclined phase axis appear at the same time, and the corresponding reflection amplitudes of the two respond. If the filling medium type in the fracture is solid (the solid specifically refers to calcite, dolomite or mudstone), then the Stoneley wave fracture imaging map, Stoneley wave reflection amplitude curve, dipole shear wave fracture imaging map, and dipole shear wave reflection amplitude curve of the well will have the following characteristics: there is no Stoneley wave fracture inclined phase axis, and there is a dipole shear wave fracture inclined phase axis.
[0063] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.
[0064] Embodiment 1
[0065] A method for identifying the filling medium type of fractures in horizontal wells in shale reservoirs, combined with Figure 1 As shown, steps S110-S150 are included, specifically:
[0066] Step S110, collecting array acoustic logging data of the target well, wherein the array acoustic logging data at least mainly includes the original waveform, gain curve and delay curve of the monopole array acoustic logging, and the original waveform, gain curve and delay curve of the dipole array acoustic logging.
[0067] In some embodiments, conventional logging data are also generally collected, and the conventional logging data at least includes a gamma curve.
[0068] Step S120, pre-processing the array acoustic logging data to obtain the waveform and time difference of the Stoneley wave and the waveform and time difference of the dipole shear wave.
[0069] The array acoustic logging data is subjected to curve preprocessing to obtain the Stoneley wave waveform, time difference and dipole shear wave waveform, time difference. In some embodiments, the arrival time of Stoneley wave and dipole shear wave is also obtained. The monopole array acoustic data preprocessing mainly includes gain recovery, delay recovery and bandpass filtering. First, gain recovery is performed, then delay recovery is performed, and finally bandpass filtering is performed. When collecting monopole array acoustic waveforms downhole, in order to ensure that the amplitude of the waveform is at the highest accuracy, automatic gain control is used during collection, so that the waveform amplitude is amplified from a decimal to an integer for easy storage and recording. Therefore, for the collected waveform, gain recovery must be performed first. The gain parameter AGN is shown in formula (1):
[0070] AGN=10 GN*0.05 (1)
[0071] Wherein, GN is the gain curve collected in step S110.
[0072] During gain recovery, the monopole array acoustic waveform is divided by AGN. During waveform acquisition, in order to reduce the storage volume of recorded data, the waveform data for a period of time before the arrival of the first wave is often not collected. The purpose of delay recovery is to fill zero before the zero moment of the monopole array acoustic waveform, so as to obtain waveform data at the accurate time. The purpose of bandpass filtering is to extract low-frequency Stoneley waves from the monopole waveform, and the frequency band range is usually selected from 600-3000Hz. Similarly, the preprocessing of dipole array acoustic wave data mainly includes gain recovery, delay recovery and bandpass filtering. The purpose of dipole array acoustic wave data preprocessing is to obtain dipole shear wave waveform data, and the frequency band range of the bandpass filter is selected as 3000-5500Hz. The conventional correlation method can be used to calculate the Stoneley wave time difference curve, arrival time curve, and dipole shear wave time difference curve and arrival time curve.
[0073] Step S130, performing noise suppression and imaging processing on the waveform of the Stoneley wave and the waveform of the dipole shear wave, respectively, to obtain a Stoneley wave crack imaging image and a dipole shear wave crack imaging image.
[0074] Specifically, Stoneley wave noise suppression mainly includes the use of FK filtering method to implement Stoneley wave direct wave suppression, thereby obtaining Stoneley wave reflection wave signals; Stoneley wave fracture imaging mainly uses the uplink and downlink wave separation method to process Stoneley wave reflection waves, thereby achieving the purpose of separating Stoneley wave uplink reflection waves from downlink reflection waves. Finally, a Stoneley wave fracture imaging image is obtained, with the left side showing the uplink reflection wave of the Stoneley wave, the middle showing the wellbore, and the right side showing the downlink reflection wave of the Stoneley wave.
[0075] Dipolar shear wave noise suppression mainly includes the use of FK filtering method to implement dipole shear wave direct wave suppression, thereby obtaining dipole shear wave reflection wave signals; dipole shear wave fracture imaging mainly uses the up-down wave separation method to process dipole shear wave reflection waves, thereby achieving the purpose of separating dipole shear wave up-down wave reflection waves from dipole shear wave down-down wave reflection waves. Finally, a dipole shear wave fracture imaging image is obtained, with dipole shear wave up-down wave reflection waves on the left, wellbore in the middle, and dipole shear wave down-down wave reflection waves on the right.
[0076] Combination Figure 2 , Figure 3 As shown, Figure 2 This is the Stoneley wave crack imaging image. Figure 3 This is a dipole shear wave crack imaging diagram. Figure 2In the figure, the first channel is the gamma curve channel, the second channel is the depth channel, the third channel is the Stoneley wave time difference, the fourth channel is the Stoneley wave arrival time curve, the fifth channel shows the original waveform of the monopole array acoustic wave, the sixth channel is the pre-processed Stoneley wave waveform, and the seventh channel is the Stoneley wave crack imaging map. Among them, the Stoneley wave time difference in the third channel and the Stoneley wave arrival time curve in the fourth channel are both curves calculated based on the Stoneley wave waveform using the time difference and arrival time extraction method. The seventh Stoneley wave crack imaging map is based on the sixth Stoneley wave waveform, and is an imaging map after direct wave suppression, multiple wave suppression, and uplink and downlink reflection wave separation processing. The left side of the figure shows the Stoneley wave uplink reflection wave, and the right side shows the Stoneley wave downlink reflection wave.
[0077] exist Figure 3 In the figure, the first channel is the gamma curve channel, the second channel is the depth channel, the third channel is the dipole shear wave time difference, the fourth channel is the dipole shear wave arrival time curve, the fifth channel shows the original waveform of the dipole array sound wave, the sixth channel is the pre-processed dipole shear wave waveform, and the seventh channel is the dipole shear wave crack imaging map. Among them, the dipole shear wave time difference in the third channel and the dipole shear wave arrival time curve in the fourth channel are both curves calculated based on the dipole shear wave waveform using the time difference and arrival time extraction method. This is an imaging image after direct wave suppression, multiple wave suppression, and uplink and downlink reflection wave separation processing based on the dipole shear wave waveform in the sixth channel. The left side of the figure shows the uplink reflection wave of the dipole shear wave, and the right side shows the downlink reflection wave of the dipole shear wave.
[0078] Step S140, calculating the Stoneley wave reflection amplitude based on the Stoneley wave fracture imaging image to obtain the Stoneley wave reflection amplitude curve of the well; calculating the dipole shear wave reflection amplitude based on the dipole shear wave fracture imaging image to obtain the dipole shear wave reflection amplitude curve of the well.
[0079] Specifically, Figure 4 This is a schematic diagram of the principle of using Stoneley wave or dipole shear wave imaging data to calculate the reflection amplitude. The horizontal axis represents time and the vertical axis represents depth. The straight line in the middle represents the wellbore, and some oblique lines represent the inclined phase axis of the fracture. Assuming that the intersection of the fracture and the wellbore is (t0,h0), if the coordinates of any point on the inclined phase axis representing the fracture are calculated (t1,h1), the relationship between the two is
[0080]
[0081] Therefore, if the time increment Δt is known, it is necessary to find its relationship with the depth increment Δh, so that the coordinates of any point on the tilted phase axis can be determined. Considering the logging process of the logging instrument and the position relationship between the sound source and the receiver in the logging instrument, the relationship between the two can be calculated as:
[0082]
[0083] Where VStoneley represents the Stoneley wave velocity, which is different from the Stoneley wave time difference D Stoneley The relationship is
[0084] V Stoneley =304800 / D Stoneley (4)
[0085] Where the unit of Stoneley wave time difference is μs / ft, and the unit of Stoneley wave velocity is m / s. Substituting equation (4) into equation (3), we can get the final relationship between and:
[0086]
[0087] Based on formula (5), the coordinates of all points on the through-well fracture passing through the depth h0 position can be calculated, and the amplitude values of all points are further added to obtain the Stoneley wave reflection amplitude at the depth position h0. According to this calculation method, the Stoneley wave reflection amplitude at different depths is calculated in turn to obtain the Stoneley wave reflection amplitude curve of the well. Figure 5 As shown in the third track.
[0088] Because there is noise interference in the actual logging data, a threshold value needs to be set. If the value is lower than the threshold value, it is considered that there is no through-well fracture at this depth, and if the value exceeds the threshold value, there is a through-well fracture. Further statistics are made on the reflection amplitude peak value exceeding the threshold value, and its corresponding depth represents the true through-well fracture depth position, and the amplitude value is positively correlated with parameters such as the through-well fracture opening.
[0089] like Figure 5 As shown in the figure, the first track is the depth track, and the second track is the imaging result of Stoneley wave passing through the wellbore fracture. The left side is the Stoneley wave upward reflection wave, the middle vertical line represents the wellbore, and the right side is the Stoneley wave downward reflection wave. A set of inclined phase axes can be observed, which represents the wellbore fracture, and the depth of intersection with the wellbore is 5604m, which represents the depth of the fracture passing through the wellbore. Figure 4 The third track in the figure is the middle curve of the Stoneley wave reflection amplitude. By setting a threshold, the random noise interference can be eliminated and the Stoneley wave reflection amplitude representing the well fracture event can be obtained, such as Figure 5 As shown in the fourth track, the depth of the event in the figure represents the depth of the through-well fracture, and the amplitude value is positively correlated with parameters such as the through-well fracture opening.
[0090] Similarly, the dipole shear wave reflection amplitude curve of the well can be obtained by the above-mentioned similar method. Specifically, the coordinates of the intersection of the fracture and the wellbore (t0, h0) are obtained from the dipole shear wave fracture imaging map, and then the coordinates of the intersection of the fracture and the wellbore and the dipole shear wave time difference D are used. SThe coordinates of any point on the inclined phase axis of the fracture are obtained; then the amplitude values of all points at the same depth h1 are added together to obtain the dipole shear wave reflection amplitude at the same depth; finally, the dipole shear wave reflection amplitudes at different depths are calculated in turn to obtain the dipole shear wave reflection amplitude curve of the well.
[0091] Using the intersection coordinates of the fracture and the wellbore, the dipole shear wave time difference D S Obtaining the coordinates of any point on the inclined phase axis of the crack includes calculating the coordinates (t1, h1) of any point on the inclined phase axis of the crack according to the following formula:
[0092]
[0093] Among them, t0 is the abscissa of the intersection of the fracture and the wellbore, representing time; h0 is the ordinate of the intersection of the fracture and the wellbore, representing depth; Δt is the known time increment, and the unknown depth increment Δh is obtained by the following formula:
[0094]
[0095] Among them, D S is the dipole shear wave time difference.
[0096] like Figure 6 As shown, Figure 6 The first track is the depth track, and the second track is the imaging result of the dipole shear wave through the wellbore fracture. The left side is the dipole shear wave upward reflection wave, the middle vertical line represents the wellbore, and the right side is the dipole shear wave downward reflection wave. A set of inclined phase axes can be observed, which represents the through-well fracture, and the depth of intersection with the wellbore is 5604m, which represents the depth of the fracture through the wellbore. Figure 5 The third track is the middle curve of the dipole shear wave reflection amplitude. By setting a threshold, the random noise interference can be eliminated and the dipole shear wave reflection amplitude representing the wellbore fracture event can be obtained, such as Figure 6 As shown in the fourth track, the depth of the event in the figure represents the depth of the through-well fracture, and the amplitude value is positively correlated with parameters such as the through-well fracture opening.
[0097] Step S150, based on the Stoneley wave fracture imaging image and the reflection amplitude curve, the dipole shear wave fracture imaging image and the dipole shear wave reflection amplitude curve, the type of the filling medium of the wellbore fracture is determined.
[0098] Specifically, the Stoneley wave fracture imaging diagram and the Stoneley wave reflection amplitude curve marked with straight lines and the dipole shear wave fracture imaging diagram and the dipole shear wave reflection amplitude curve marked with straight lines are put together for comparative analysis. Based on the rules mentioned in the embodiment of the present invention, it is possible to determine whether the fracture filling medium type is solid or fluid. That is, if at a certain depth, the Stoneley wave fracture inclined phase axis and the dipole shear wave fracture inclined phase axis appear at the same time, and the corresponding reflection amplitudes of the two respond, it means that there is a through-well fracture at this depth, and the type of filling medium in the fracture is fluid. If at a certain depth, there is no Stoneley wave fracture inclined phase axis, but there is a dipole shear wave fracture inclined phase axis, it means that there is a through-well fracture at this depth, and the type of filling medium in the fracture is solid.
[0099] Combination Figure 7 , Figure 8 As shown, Figure 7 The second track is the Stoneley wave through-well fracture imaging image, and the third track is the Stoneley wave reflection amplitude. From it, we can observe the depth of 5604m. Both the Stoneley wave imaging image and the Stoneley wave reflection amplitude show that there is a through-well fracture at this location. Figure 7 The fourth track is a dipole shear wave through-well fracture imaging image, and the fifth track is a dipole shear wave reflection amplitude. It can be observed that at the same depth of 5604m, both the dipole shear wave imaging image and the dipole shear wave reflection amplitude show that there are through-well fractures at this location. Combining the numerical simulation of the horizontal wellside fracture model of shale reservoirs and the physical experimental simulation law, considering that both mode waves have through-well fracture responses at this depth, this shows that the fracture filling medium type at the above depth is fluid, which may be oil, natural gas or water.
[0100] Figure 8 The second track is the Stoneley wave through-well fracture imaging image, and the third track is the Stoneley wave reflection amplitude. From it, we can observe the position of 3723m depth. Both the Stoneley wave imaging image and the Stoneley wave reflection amplitude show that there is a through-well fracture at this position. Figure 8 The fourth track is the dipole shear wave through-well fracture imaging, and the fifth track is the dipole shear wave reflection amplitude, from which no through-well fracture signal can be observed. Combining the numerical simulation of the horizontal wellside fracture model of shale reservoirs and the physical experimental simulation law, considering that only Stoneley waves respond at a depth of 3723m, but not dipole shear waves, it is determined that the fracture filling medium type at this depth is solid, which may be calcite, dolomite or mud.
[0101] Based on numerical simulation and physical experiments of a large number of horizontal wellside fracture models in shale reservoirs, the present invention finds that array acoustic logging data can be used to identify the type of filling medium in wellside fractures, so that the Stoneley wave fracture imaging map and reflection amplitude curve, dipole shear wave fracture imaging map and dipole shear wave reflection amplitude curve of the target well to be identified are obtained respectively, and comparative analysis is performed to determine whether the filling medium type of wellside fractures is fluid or solid. The embodiment of the present invention can efficiently and accurately identify the filling medium type in the fracture as fluid or solid, overcoming the shortcomings of the prior art.
[0102] Embodiment 2
[0103] Correspondingly, the present invention also discloses a device for identifying the type of filling medium for a horizontal well bypassing a shale reservoir, such as Fig. 9 As shown, it includes a logging data collection module 10, a logging data preprocessing module 20, a fracture imaging module 30, a reflection amplitude curve generation module 40, and a recognition module 50, wherein:
[0104] The logging data collection module 10 is used to collect conventional logging data and array acoustic logging data of the target well, wherein the conventional logging data at least includes a gamma curve; the array acoustic logging data at least mainly includes a monopole array acoustic original waveform, a gain curve and a delay curve, and a dipole array acoustic logging original waveform, a gain curve and a delay curve.
[0105] The logging data preprocessing module 20 is used to preprocess the array acoustic logging data to obtain the waveform and time difference of the Stoneley wave and the waveform and time difference of the dipole shear wave.
[0106] The array acoustic logging data is subjected to curve preprocessing to obtain the Stoneley wave waveform, time difference and dipole shear wave waveform, time difference. The monopole array acoustic data preprocessing mainly includes gain recovery, delay recovery and bandpass filtering. First, gain recovery is performed, then delay recovery is performed, and finally bandpass filtering is performed. When collecting monopole array acoustic waveforms underground, in order to ensure that the amplitude of the waveform is at the highest accuracy, automatic gain control is used during collection, so that the waveform amplitude is amplified from a decimal to an integer for easy storage and recording. Therefore, for the collected waveform, gain recovery must be performed first. The gain parameter AGN is shown in formula (1):
[0107] AGN=10 GN*0.05 (1)
[0108] Among them, GN is the collected gain curve.
[0109] During gain recovery, the monopole array acoustic waveform is divided by AGN. During waveform acquisition, in order to reduce the storage volume of recorded data, the waveform data for a period of time before the arrival of the first wave is often not collected. The purpose of delay recovery is to fill zero before the zero moment of the monopole array acoustic waveform, so as to obtain waveform data at the accurate time. The purpose of bandpass filtering is to extract low-frequency Stoneley waves from the monopole waveform, and the frequency band range is usually selected from 600-3000Hz. Similarly, the preprocessing of dipole array acoustic wave data mainly includes gain recovery, delay recovery and bandpass filtering. The purpose of dipole array acoustic wave data preprocessing is to obtain dipole shear wave waveform data, and the frequency band range of the bandpass filter is selected as 3000-5500Hz. The conventional correlation method can be used to calculate the Stoneley wave time difference curve, arrival time curve, and dipole shear wave time difference curve and arrival time curve.
[0110] The crack imaging module 30 is used to perform noise suppression and imaging processing on the waveform of the Stoneley wave and the waveform of the dipole shear wave, respectively, to obtain a Stoneley wave crack imaging image and a dipole shear wave crack imaging image.
[0111] Specifically, Stoneley wave noise suppression mainly includes the use of FK filtering method to implement Stoneley wave direct wave suppression, thereby obtaining Stoneley wave reflection wave signals; Stoneley wave fracture imaging mainly uses the uplink and downlink wave separation method to process Stoneley wave reflection waves, thereby achieving the purpose of separating Stoneley wave uplink reflection waves from downlink reflection waves. Finally, a Stoneley wave fracture imaging image is obtained, with the left side showing the uplink reflection wave of the Stoneley wave, the middle showing the wellbore, and the right side showing the downlink reflection wave of the Stoneley wave.
[0112] Dipolar shear wave noise suppression mainly includes the use of FK filtering method to implement dipole shear wave direct wave suppression, thereby obtaining dipole shear wave reflection wave signals; dipole shear wave fracture imaging mainly uses the up-down wave separation method to process dipole shear wave reflection waves, thereby achieving the purpose of separating dipole shear wave up-down wave reflection waves from dipole shear wave down-down wave reflection waves. Finally, a dipole shear wave fracture imaging image is obtained, with dipole shear wave up-down wave reflection waves on the left, wellbore in the middle, and dipole shear wave down-down wave reflection waves on the right.
[0113] The reflection amplitude curve generating module 40 is used to calculate the Stoneley wave reflection amplitude based on the Stoneley wave fracture imaging image to obtain the Stoneley wave reflection amplitude curve of the well; calculate the dipole shear wave reflection wave amplitude based on the dipole shear wave fracture imaging image to obtain the dipole shear wave reflection amplitude curve of the well.
[0114] Specifically, Figure 4This is a schematic diagram of the principle of using Stoneley wave or dipole shear wave imaging data to calculate the reflection amplitude. The horizontal axis represents time and the vertical axis represents depth. The straight line in the middle represents the wellbore, and some oblique lines represent the inclined phase axis of the fracture. Assuming that the intersection of the fracture and the wellbore is (t0,h0), if the coordinates of any point on the inclined phase axis representing the fracture are calculated (t1,h1), the relationship between the two is
[0115]
[0116] Therefore, if Δt is known, its relationship with Δh needs to be found, and the coordinates of any point on the tilted phase axis can be determined. Considering the logging process of the logging instrument and the position relationship between the sound source and the receiver in the logging instrument, the relationship between the two can be calculated as:
[0117]
[0118] Where V Stoneley represents the Stoneley wave velocity, which is different from the Stoneley wave time difference D Stoneley The relationship is
[0119] V Stoneley =304800 / D Stoneley (4)
[0120] Where the unit of Stoneley wave time difference is μs / ft, and the unit of Stoneley wave velocity is m / s. Substituting equation (4) into equation (3), we can get the final relationship between and:
[0121]
[0122] Based on formula (5), the coordinates of all points on the through-well fracture passing through the depth h0 position can be calculated, and the amplitude values of all points are further added to obtain the Stoneley wave reflection amplitude at the depth position h0. According to this calculation method, the Stoneley wave reflection amplitude at different depths is calculated in turn to obtain the Stoneley wave reflection amplitude curve of the well. Figure 5 As shown in the third track.
[0123] Because there is noise interference in the actual logging data, a threshold value needs to be set. If the value is lower than the threshold value, it is considered that there is no through-well fracture at this depth, and if the value exceeds the threshold value, there is a through-well fracture. Further statistics are made on the reflection amplitude peak value exceeding the threshold value, and its corresponding depth represents the true through-well fracture depth position, and the amplitude value is positively correlated with parameters such as the through-well fracture opening.
[0124] Similarly, the dipole shear wave reflection amplitude curve of the well can be obtained by the above-mentioned similar method. Specifically, the coordinates of the intersection of the fracture and the wellbore (t0, h0) are obtained from the dipole shear wave fracture imaging map, and then the coordinates of the intersection of the fracture and the wellbore and the dipole shear wave time difference D are used. SThe coordinates of any point on the inclined phase axis of the fracture are obtained; then the amplitude values of all points at the same depth h1 are added together to obtain the dipole shear wave reflection amplitude at the same depth; finally, the dipole shear wave reflection amplitudes at different depths are calculated in turn to obtain the dipole shear wave reflection amplitude curve of the well.
[0125] Using the intersection coordinates of the fracture and the wellbore, the dipole shear wave time difference D S Obtaining the coordinates of any point on the inclined phase axis of the crack includes calculating the coordinates (t1, h1) of any point on the inclined phase axis of the crack according to the following formula:
[0126]
[0127] Among them, t0 is the abscissa of the intersection of the fracture and the wellbore, representing time; h0 is the ordinate of the intersection of the fracture and the wellbore, representing depth; Δt is the known time increment, and the unknown depth increment Δh is obtained by the following formula:
[0128]
[0129] Among them, D S is the dipole shear wave time difference.
[0130] The identification module 50 is used to identify the type of filling medium of the wellbore fracture based on the Stoneley wave fracture imaging image and the reflection amplitude curve, the dipole shear wave fracture imaging image and the dipole shear wave reflection amplitude curve.
[0131] Specifically, the Stoneley wave fracture imaging map, reflection amplitude curve, dipole shear wave fracture imaging map, and dipole shear wave reflection amplitude curve are compared and analyzed. If at a certain depth, the Stoneley wave fracture inclined phase axis and the dipole shear wave fracture inclined phase axis appear at the same time, and the corresponding reflection amplitudes of the two respond, it is judged that there is a through-well fracture at this depth, and the type of filling medium in the fracture is fluid; if at a certain depth, there is no Stoneley wave fracture inclined phase axis, but there is a dipole shear wave fracture inclined phase axis, it means that there is a through-well fracture at this deep position, and the type of filling medium in the fracture is solid.
[0132] The schematic diagram of the output of each module of the device for identifying the type of filling medium for a horizontal well bypassing a shale reservoir fracture can be referred to in Example 1, and will not be described in detail here.
[0133] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are clearly stated in each claim. On the contrary, as reflected in the appended claims, the invention is in a state of having less than all the features of the disclosed individual embodiments. Therefore, the appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.
[0134] The above description includes examples of one or more embodiments. Of course, it is not possible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the word is encompassed in a manner similar to the term "including", as explained by "including," used as a transitional word in the claims. In addition, any term "or" used in the specification of the claims is intended to mean "non-exclusive or".
Claims
1. A method for identifying the type of filling medium for horizontal well bypass fractures in shale reservoirs, characterized in that: The following steps are involved: Collecting array acoustic logging data of the target well, wherein the array acoustic logging data at least mainly includes the original waveform, gain curve and delay curve of the monopole array acoustic logging, and the original waveform, gain curve and delay curve of the dipole array acoustic logging; Preprocess the array acoustic logging data to obtain the waveform and time difference of Stoneley wave, the waveform and time difference of dipole shear wave; Perform noise suppression and imaging processing on the waveform of Stoneley wave and the waveform of dipole shear wave respectively to obtain Stoneley wave crack imaging map and dipole shear wave crack imaging map; The Stoneley wave reflection amplitude is calculated based on the Stoneley wave fracture imaging image to obtain the Stoneley wave reflection amplitude curve of the well; the dipole shear wave reflection amplitude is calculated based on the dipole shear wave fracture imaging image to obtain the dipole shear wave reflection amplitude curve of the well; The type of filling medium of the fractures near the wellbore is identified based on the Stoneley wave fracture imaging map, reflection amplitude curve, dipole shear wave fracture imaging map, and dipole shear wave reflection amplitude curve.
2. The identification method according to claim 1, characterized in that: The array acoustic logging data is preprocessed to obtain the waveform and time difference of Stoneley waves and the waveform and time difference of dipole shear waves, including: The array acoustic logging data are subjected to gain recovery, delay recovery and bandpass filtering to obtain the waveform and time difference of Stoneley waves and the waveform and time difference of dipole shear waves respectively.
3. The identification method according to claim 2, characterized in that: The gain recovery, delay recovery and bandpass filtering of the array acoustic logging data include: Gain recovery is performed according to the following gain parameter AGN: AGN=10 GN*0.05 Wherein, GN is the collected gain curve; For monopole array acoustic logging data, the frequency band of the bandpass filter is 600 Hz-3000 Hz, and for dipole array acoustic logging data, the frequency band of the bandpass filter is 3000 Hz-5500 Hz.
4. The identification method according to claim 1, characterized in that: The method of performing noise suppression and imaging processing on the waveform of the Stoneley wave and the waveform of the dipole shear wave respectively to obtain a Stoneley wave crack imaging image and a dipole shear wave crack imaging image comprises: FK filtering is used to suppress noise on the waveform of Stoneley wave and the waveform of dipole shear wave respectively, so as to obtain the reflected wave signal of Stoneley wave and the reflected wave signal of dipole shear wave; The uplink and downlink waves of the Stoneley wave reflection signal are separated to obtain two Stoneley wave uplink reflection waves and downlink reflection waves, with a Stoneley wave fracture imaging map of the wellbore in the middle; the uplink and downlink waves of the dipole shear wave reflection signal are separated to obtain two Stoneley wave uplink reflection waves and downlink reflection waves, with a Stoneley wave fracture imaging map of the wellbore in the middle.
5. The identification method according to claim 1, characterized in that: The method of calculating the Stoneley wave reflection amplitude based on the Stoneley wave fracture imaging image to obtain the Stoneley wave reflection amplitude curve of the well includes: The coordinates of the intersection of the fracture and the wellbore are obtained from the Stoneley wave fracture imaging map; The coordinates of any point on the inclined event axis of the fracture are obtained by using the coordinates of the intersection of the fracture and the wellbore and the time difference of the Stoneley wave; The amplitude values of all points at the same depth are summed to obtain the Stoneley wave reflection amplitude at the same depth; The Stoneley wave reflection amplitudes at different depths are calculated in sequence to obtain the Stoneley wave reflection amplitude curve of the well.
6. The identification method according to claim 5, characterized in that: The method of obtaining the coordinates of any point on the inclined event axis of the fracture using the coordinates of the intersection of the fracture and the wellbore and the time difference of the Stoneley wave includes calculating the coordinates of any point on the inclined event axis of the fracture according to the following formula: Among them, t0 is the abscissa of the intersection of the fracture and the wellbore, representing time; h0 is the ordinate of the intersection of the fracture and the wellbore, representing depth; the coordinates of any point on the inclined phase axis of the fracture are (t1, h1); Δt is the known time increment, and the unknown depth increment Δh is obtained by the following formula: Among them, D Stoneley The Stoneley wave time difference.
7. The identification method according to claim 1, characterized in that: The method of calculating the dipole shear wave reflection wave amplitude based on the dipole shear wave fracture imaging image to obtain the dipole shear wave reflection amplitude curve of the well includes: The coordinates of the intersection of the fracture and the wellbore are obtained from the dipole shear wave fracture imaging map; The coordinates of any point on the inclined phase axis of the fracture are obtained by using the coordinates of the intersection of the fracture and the wellbore and the time difference of the dipole shear wave; The amplitude values of all points at the same depth are summed to obtain the dipole shear wave reflection amplitude at the same depth; The dipole shear wave reflection amplitudes at different depths are calculated in sequence to obtain the dipole shear wave reflection amplitude curve of the well.
8. The identification method according to claim 7, characterized in that: The method of obtaining the coordinates of any point on the inclined event axis of the fracture using the coordinates of the intersection of the fracture and the wellbore and the time difference of the dipole shear wave includes calculating the coordinates of any point on the inclined event axis of the fracture according to the following formula: Among them, t0 is the abscissa of the intersection of the fracture and the wellbore, representing time; h0 is the ordinate of the intersection of the fracture and the wellbore, representing depth; the coordinates of any point on the inclined phase axis of the fracture are (t1, h1); Δt is the known time increment, and the unknown depth increment Δh is obtained by the following formula: Among them, D S is the dipole shear wave time difference.
9. The identification method according to claim 1, characterized in that: The method of identifying the type of filling medium of the wellbore fracture based on the Stoneley wave fracture imaging map, the reflection amplitude curve, the dipole shear wave fracture imaging map, and the dipole shear wave reflection amplitude curve includes: If at a certain depth, both the Stoneley wave fracture inclined phase axis and the dipole shear wave fracture inclined phase axis appear, and the corresponding reflection amplitudes of the two respond, it is judged that there is a through-well fracture at this depth, and the filling medium type in the fracture is fluid; if at a certain depth, there is no Stoneley wave fracture inclined phase axis, but there is a dipole shear wave fracture inclined phase axis, it means that there is a through-well fracture at this depth, and the filling medium type in the fracture is solid.
10. A device for identifying the type of filling medium for horizontal well bypass fractures in shale reservoirs, characterized in that: It includes logging data collection module, logging data preprocessing module, fracture imaging module, reflection amplitude curve generation module and identification module, among which: The logging data collection module is used to collect array acoustic logging data, wherein the array acoustic logging data at least mainly includes the original waveform, gain curve and delay curve of the monopole array acoustic wave, and the original waveform, gain curve and delay curve of the dipole array acoustic wave logging; The logging data preprocessing module is used to preprocess the array acoustic logging data to obtain the waveform and time difference of the Stoneley wave and the waveform and time difference of the dipole shear wave respectively; The crack imaging module is used to perform noise suppression and imaging processing on the waveform of the Stoneley wave and the waveform of the dipole shear wave, respectively, to obtain a Stoneley wave crack imaging image and a dipole shear wave crack imaging image; The reflection amplitude curve generating module is used to calculate the Stoneley wave reflection amplitude based on the Stoneley wave fracture imaging map to obtain the Stoneley wave reflection amplitude curve of the well; calculate the dipole shear wave reflection wave amplitude based on the dipole shear wave fracture imaging map to obtain the dipole shear wave reflection amplitude curve of the well; The identification module is used to identify the type of filling medium of the wellbore fracture based on the Stoneley wave fracture imaging image and reflection amplitude curve, the dipole shear wave fracture imaging image and the dipole shear wave reflection amplitude curve.
11. The identification device according to claim 11, characterized in that: The identification module is specifically used to compare and analyze the Stoneley wave fracture imaging map, the reflection amplitude curve, the dipole shear wave fracture imaging map, and the dipole shear wave reflection amplitude curve. If at a certain depth position, the Stoneley wave fracture tilted event axis and the dipole shear wave fracture tilted event axis appear at the same time, and the corresponding reflection amplitudes of the two respond, it is determined that there is a through-well fracture at the depth position, and the filling medium type in the fracture is fluid; If at a certain depth, there is no Stoneley wave fracture inclined phase axis, but there is a dipole shear wave fracture inclined phase axis, it means that there is a through-well fracture at this depth, and the filling medium type in the fracture is solid.